.head,.footer,.main{
    width: 500px;
}
.head,.footer{
    height: 100px;
    background-color: #009900;
}
.main{
    height: 300px;
    background-color: gray;
}
.left,.right{
    width: 100px;
    height: 300px;
    background-color: blue;
}
.right{
    float: right;
}
.left{
    float: left;
}
.content{
    width: 300px;
    height: 300px;
    background-color: black;
float: left;
}
.content .top{
    width: 300px;
    height: 150px;
    background-color: #c9e143;
}
.content .bot{
    width: 300px;
    height: 150px;
    background-color: pink;
}